(1) Storage Area Network
A network that connects one or more computers and one or more external storage apparatuses is called a “storage area network (SAN)”. A storage area network is a computer system that is used especially frequently in a case where multiple computers cooperate to provide a single function or when multiple computers share one large capacity storage device. A storage area network facilitates easier subsequent addition, elimination, or replacement of storage resources or computer resources, and has the advantage of having excellent extensibility.
(2) Disk Array Apparatus
Generally, a disk array apparatus is frequently utilized for an external storage apparatus that is connected to a SAN. A disk array apparatus is an apparatus in which a large number of magnetic storage devices typified by a hard disk are mounted.
The disk array apparatus manages multiple magnetic storage devices as a single group using RAID (Redundant Array of Independent Disks) technology. A group of magnetic storage devices is called a “RAID group”. A RAID group forms one or more logical storage areas. A computer that is connected to a SAN executes data input/output processing with respect to the storage area. When recording data in the storage area, the disk array apparatus records one or two pieces of redundant data among the magnetic storage devices constituting the RAID group. Because of the existence of the redundant data, there is the advantage that even in a situation in which one of the magnetic storage devices breaks down, it is possible to restore the data from the remaining magnetic storage devices within the RAID group.
(3) Power Consumption Management Method
Patent Citation 1 discloses technology that manages power that a storage system consumes. According to this technology, it is possible to compute the power consumption by a calculation that takes a workload (number of I/Os, transfer data amount) produced by storage processing as a variable, and output the result to a management screen. At such time, the technology does not simply output the power consumption, but outputs the power consumption in combination with the workload (IOPS, MB/sec).
Further, when a workload exceeds a predetermined threshold value, the technology can concentrate a storage area into one portion of the magnetic storage devices, and save power consumption by stopping magnetic storage devices that have become empty.
(4) Utility Service
Service providers such as Saas or Paas provide a service that lends out storage capacity to clients via a network. Clients can make practical use of storage resources across a network.